Brake control for high speed trains



c. c. FARMER ET AL 2,109,166

Filed Sept. 17, 1935 5 Sheets-Sheet 1 M m2 P55? Feb. 22, 1938.

BRAKE CONTROL FOR HIGH SPEED TRAINS m QQ w. n

ATTORN EY F 1938. c. c. FARMER ET AL 2,109,166

BRAKE CONTROL FOR HIGH SPEED TRAINS ELLIS E, HEWITT.

r2 BY%% ATTORNEY Patented Feb. 22, 1938 BRAKE CONTROL FOR HIGH SPEEDTRAINS Clyde C.

Farmer, Pittsburgh, and Ellis E. Hewitt,

Edgewood, Pa., assignors to The Westinghouse Air Brake Company,Wilmerding, Pa., a corporation of Pennsylvania Application September 17,1935, Serial No. 40,902

82 Claims.

This invention relates to brake control for high speed trains, and hasparticular relation to devices for adapting present standard brakecontrol equipment for high speed service.

In the present standard brake equipment for steam road passengerservice, the brake controlling valve device commonly employed is thewell known Westinghouse universal valve which is adapted to supply fluidunder pressure from the usual auxiliary reservoir, service reservoir,and emergency reservoir to the brake cylinder in such manner that themaximum brake cylinder pressure attainable in an emergency applicationof the brakes is approximately seventy-five pounds per square inch,which effects a braking ratio of about one hundred and fifty per cent.The term braking ratio as employed herein, should be understood as theratio between the braking force, that is, the total pressure of thebrake shoes upon the car wheels, and the empty weight of the car, theratio being expressed as per cent of the empty weight of the car. It hasbeen found that for speeds up to sixty miles per hour in passengerservice, a braking ratio of one hundred and fifty per cent in emergencyapplications is satisfactory in that such braking ratio imparts the mosteffective retardation or braking action with only a moderate amount ofwheel sliding at the lower speeds.

It is now proposed to employ present standard passenger cars in highspeed service wherein the normal speed of travel may attain the degreeof one hundred miles per hour or more. With the present brake equipmenton passenger cars, the stopping distance will be greatly lengthened overthe normal stopping distance in decelerating from speeds higher than thepresent maximum speeds due to the increased amount of kinetic energystored in the moving train, the energy being proportional to the squareof the velocity or speed of the train. It will thus be apparent that inorder to stop a train in substantially the same distance, from a speedof one hundred miles per hour as from a speed of sixty miles per hour,approximately three times as much braking effort or work must beexpended. Furthermore, the heat generated in the brake shoes is greaterwhen the speed of the train at the time the application of the brakes isinitiated is relatively high as compared to the heat generated in thebrake shoes when the speed of the train at the time an application ofthe brakes is initiated is relatively low, and as is well known thecoeflicient oi. friction between a brake shoe and its associated carwheel decreases as the heat developed in the brake shoes increases. Thisfactor in itself, therefore, also necessitates the application ofgreater braking force in order to bring a train to a stop in the samedistance from a higher speed as from a lower speed.

Since present standard brake equipment for passenger cars is not adaptedto provide more than a one hundred and fifty per cent braking ratio, andsince high speed service requires higher braking ratios than one hundredand fifty per cent, it will be apparent that brake control equipment,especially designed for high speed service, or equipment, supplementalto the present standard brake equipment and functioning to adapt thestandard brake equipment for high speed service, is necessary.

In view of the fact that it would be an extremely costly undertaking toscrap all of the present standard brake equipment on passenger cars andalso in View of the fact that such equipment may still be in aserviceable condition, it is desirable to modify the present standardbraking equipment for passenger cars, by providing supplementalequipment adapted to function in cooperation therewith for high speedservice, the cost of conversion being less than the cost of replacingthe present standard braking equipment with new equipment especiallydesigned for high speed service.

It is, therefore, an object of our invention to provide supplementalequipment to be used in conjunction with present standard brake controlequipment on passenger cars, which supplemental equipment adapts presentstandard braking equipment for use in high speed service.

Another object of our invention is to provide supplemental equipment tobe used in conjunction with present standard brake control equipment onpassenger cars, whereby higher brake cylinder pressures and accordinglyhigher braking ratios may be attained relative to the brake cylinderpressures and braking ratios attainable with present standard brakeequipment, in order to enable a train to be stopped in substantially thesame distance upon the initiation of a brake application at a relativelyhigh speed as upon the initiation of a brake application at a lowerspeed.

Another object of our invention is to provide brake control equipmentadapted to automatically select different braking ratios dependent uponthe speed of the train at the time an application of the brakes isinitiated.

Another object of our invention is to provide brake control equipment ofthe above character, adapted to automatically reduce brake cylinderpressure and accordingly the braking ratio, as the train decreases inspeed upon an application of the brakes, to prevent sliding of thewheels.

A further object of our invention is to provide brake control equipmentadapted to function automatically to reduce the brake cylinder pressureand accordingly the braking ratio as the speed of the train reduces to arelatively low degree upon an application of the brakes, the degree towhich the brake cylinder pressure and braking ratio is finally reducedbeing diiferent, depend ent upon the speed of the train at the time theapplication of the brakes was initiated, compensation for variations inthe coefficient of friction between the brake shoes and car wheelsoccasioned as a result of the initial application of the brake shoes tothe car wheels at difierent speeds, being thus automatically effected.

The above objects, and other objects of our invention which will be madeapparent hereinafter, are attained by means of illustrative embodimentsof our invention shown in the accompanying drawings, wherein Figure l isa diagrammatic view, partly in section, showing one embodiment of ourinvention,

Figure 2 is a fragmentary diagrammatic view, illustrating a mechanismfor operating one of the switch devices shown in Figure 1,

Figure 3 is a diagrammatic view, partly in section, illustrating anotherembodiment of our invention,

Figure 4 is a diagrammatic view, partly in section, illustrating amodified valve mechanism which may be substituted for the correspondingvalve mechanism shown in Figure 3,

Figure 5 is another illustrative embodiment of our invention, and

Figure 6 is a diagrammatic view, partly in section, illustrating amodified valve mechanism which may be substituted for the correspondingvalve mechanism shown in Figure 5.

Referring to Figure 1, the equipment shown therein comprises the usualpassenger car equipment including a brake pipe ll, auxiliary reservoirI2, service reservoir l3, emergency reservoir M, a brake controllingvalve device [5 for passenger cars, such as the well known Westinghouseuniversal valve, and brake cylinder [6. Since the operation of thisstandard brake equipment for passenger cars is well known, it is deemedunnecessary to show and describe the details of construction orspecifically explain the operation thereof, except to note that theemergency reservoir l4 and the brake cylinder l6 differ from the presentstandard equipment as to relative capacities, in order to enable higherbrake cylinder pressure tobe attained in the manner hereinafterdescribed.

In accordance with our invention, equipment supplemental to the standardbrake equipment for passenger cars is employed, comprising asupplemental valve mechanism l8, for regulating the fluid under pressuresupplied from the reservoirs to the brake cylinder 16 under the controlof valve device l5, and thereby determining the braking ratio, acentrifugal governor device IS, a fluid pressure operated electricswitch device 2!, a circuit-maintaining relay 22 of self-holding type,and a switch device 23 associated with the support for the governordevice [9.

The supplemental valve mechanism l8 comprises an electromagnet valvecasing section 25 and a controlling valve casing section 26.

Included in the casing section 26 is an inshot valve device 28comprising a disc valve 29 guidably mounted in a chamber 3| which isconnected to the brake cylinder supply port of the valve device l5through a pipe 32 and branch pipe 33. The valve 29 is normallymaintained unseated from a cooperating annular ribseat 34 on a threadedcollar 35 screwed into the chamber 3|, by a stem 36 which extendsthrough a passage 3'! in the collar 35 and which is secured to a piston38 mounted in a chamber 39, the piston being normally biased to unseatthe valve 29 by a coil spring 4| interposed between the piston 38 and ascrew plug 42. The screw plug 42 is threaded into an. internallythreaded collar 43 which is in turn threaded into the open end of thechamber 39, the inner end of the collar serving to limit the downwardmovement of the piston 38. The piston 38 has a stem 44 which extendsslidably through a hole 45 in the plug 42 to the exterior of the casing,and the stem 44 is provided on the outer threaded end thereof with a nut46 and lock nut 41 adapted to limit the upward movement of the piston 38by the spring 4 l upon engagement of the nut 46 with the outer surfaceof the plug 42. The collar 35 has a chamber 48 which is an enlargedportion of passage 31, the chamber being connected through a port 52 inthe wall of the collar toa passage 49 in the casing leading to anotherpassage 5|.

A disc type cut-off valve 53, which is guidably mounted in a chamber 54and which cooperates with an annular rib seat 55, serves to controlcommunication through a passage 56 from chamber 54 and passage 5| whichopens into chamber 54, to a passage and pipe 51 leading to the brakecylinder 16.

The valve 53 is urged toward the annular rib seat 55 by a coil spring 59interposed between the valve and a screw plug 6! closing the chamber 54,and is normally unseated against the force of spring 59, as will bedescribed hereinafter.

A check valve 61, disposed in a chamber 65, and cooperating with a valveseat formed on the inner face of a screw plug 64 screwed into andclosing the chamber 65, is adapted to prevent flow of fluid underpressure around the cut-off valve 53 from the chamber 54 to the brakecylinder passage 5'! and to permit reverse flow of fluid under pressurefrom the brake cylinder passage 5'! to chamber 54, through a passage 62,a passage 63 in the screw plug opening at the valve seat therein,chamber 65 and a passage 66, for a reason which will be made apparenthereinafter.

The supplemental valve mechanism l8 further comprises a valve piston Hslidably movable in a bore I0 and having a chamber 12 at one sidethereof and a chamber l3 at the opposite side thereof. The valve pistonH has an annular gasket 14, inset in the face thereof open towardchamber 13, adapted to engage an annular rib seat 75, of smallerdiameter than the bore 16', when the piston is at one extremity of itsmovement, and has also an annular rib 76 on theopposite face thereofadapted to engage a gasket Tl interposed between casing sections 25 and26, when the valve piston is moved to the opposite extremity of itsmovement. A coil spring (8 disposed in the chamber 12 between one faceof the valve piston H and the casing section 25 urges the valve pistoninto engagement with the annular rib seat 15.

The valve piston 'H has a chamber or recess 19 opening at the facethereof into chamber 13, which chamber 19 contains a disc type valve 8|guidably mounted therein and yieldingly urged into seated relation on anannular rib seat 82 by a spring 83 interposed in the chamber 19 betweenthe valve 8| and the valve piston 1|. A collar 84 threaded into thevalve piston 1| at the open end of the recess 19 is adapted toengage theprojecting guide lugs on the valve 8| to limit the outward movement ofthe valve 8| in the recess 19, the valve 8| being thus unseated from theannular rib seat 82 when the valve piston 1| is moved away from theannular rib seat 15.

The valve 8| controls a communication between chamber 3| of the inshotvalve device 28 and the passage 5|, the passage 5| terminating at theinner seated area of the valve 8|, and the chamber 3| being incommunication with chamber 13, at a point inside the annular rib seat15, through a passage 86. Thus when valve 8| is unseated from the ribseat 82, a communication from the brake cylinder supply pipe 32 to thebrake cylinder passage 5|, in parallel with that controlled by the valve29 is established.

The chamber 12 at the one side of the valve piston 1| is normallysupplied with fluid under pressure from a suitable reservoir, such asthe emergency reservoir I4, for holding the valve piston 1| seated onthe rib seat 15 against the pressure of the fluid supplied to the brakecylinder through pipe 32, and acting on the opposite face of the valvepiston in chamber 13.

For the purpose of controlling the supply of fluid under pressure to andthe release of fluid under pressure from the chamber 12, anelectromagnet valve device 88 is provided in the casing section 25,comprising a suitable electromagnet 90, for operating a double beatvalve 89 disposed in a chamber 9| which is in constant communicationwith the chamber 12 through a passage 92. When the electromagnet 90 ofthe magnet valve device 88 is deenergized the double beat valve 89 isurged into seated relation on a valve seat 93 to close communicationbetween the chamber 9| and an atmospheric chamber 94, and tosimultaneously open communication between the chamber 9| and a chamber95 which is connected to a suitable reservoir, such as the emergencyreservoir I4, through the pipe 96. A spring 91 contained in the chamber95 and interposed between a collar, secured to a fluted stem of thedouble beat valve 89, and a screw plug 98 closing the chamber 95, isprovided for yieldingly urging the double beat valve into seatedrelation on the valve seat 93.

When the electromagnet 90 of the magnet valve device 88 is energized,the double beat valve 89 is moved against the force of the spring 91into seated relation on a valve seat 99 to close the communication fromchamber 95 to chamber 9 I, and is simultaneously unseated from the valveseat 93 to open communication from the cham ber 9| to the atmosphericchamber 94.

The supplemental valve mechanism I8 also further comprises a valvepiston IOI slidably movable in a bore I and having a chamber I02 at oneside thereof and a chamber I03 at the other side thereof. Inset in theface of the valve piston IOI open toward chamber I03 is an annulargasket I04 which engages an annular rib seat I05, the other face of thevalve piston having an annular rib I00 thereon which is adapted toengage, in sealing relation, a gasket I01 interposed between the casingsections 25 and 26. A coil spring I08 disposed in the chamber I02 andinterposed between the valve piston IM and the casing section 25 servesto yieldingly urge the valve piston IOI into seated relation on theannular rib seat I05.

The valve piston IOI has a chamber or recess I09 in the face thereofopening into the chamber I03, in which chamber I09 is guidably mount eda disc type valve I I0 which is yieldingly urged into seated relation onan annular rib seat III by a spring ||2 contained in chamber I09 andinterposed between'the valve H0 and the valve piston IN.

A threaded collar II3 screwed into the face of the valve piston IOI atthe open end of the chamber I09 is adapted to engage the projectingguide lugs of the valve I I0 and to unseat the valve from the annularrib seat III, as the valve piston |0I is moved away from the annular ribseat I05.

The inner seated area of the valve 0 is in communication with the brakecylinder passage 51 through a passage H5, and the chamber I03 is incommunication with a suitable blow-down or pressure valve device II1through a passage 8 opening inside the annular rib seat I05, When seatedon the rib seat III, the valve |I0 closes the passage H and thus closesofi communication between the passage 51 and the blowdown valve H1, andwhen unseated opens communication between the passage 51 and theblowdown valve II1.

Blow-down valve 1 is set to maintain a predetermined brake cylinderpressure, such as fifty pounds per square inch, which is adequate tostop the car or train but which is insufiicient to cause sliding of thewheels at the lower speeds.

In order to cause the cut-01f valve 53 to be unseated from the annularrib seat 55 and thereby permit a supply of fluid under pressure from thepipe 32 and passage 5| to the brake cylinder passage 51, a stem I2I isprovided which extends through passages 56 and H5 and which has itsopposite ends engaging the valves H0 and 53, respectively, the stem I2Ibeing of sufficient length to maintain the valve 53 unseated as long asthe valve I I0 is seated on the annular rib seat III. In this connectionit should be understood that the tension of spring H2 is effective, whenthe valve piston IOI is held on the rib seat I05 by the pressure offluid in chamber I02, to hold the valve I I0 on the annular rib seat III against the opposing force of spring 59 exerted through valve 53 andstem |2I and the maximum brake cylinder pressure exerted on the innerseated area of valve IIU through passage II5. When the valve H0 isunseated from the rib seat III to establish communication between thebrake cylinder passage 51 and the blow-down valve I I1, the spring 59 issimultaneously eiiective to move the valve 53 into seated relation onthe rib seat 55 to cut off the supply of fluid under pressure throughthe passage 56 from the passage 5| to the brake cylinder passage 51.

The supply of fluid under pressure to and the release of fluid underpressure from the chamber I02 is controlled by a magnet valve device I23comprising an electromagnet I22 and a double beat valve I24 operated bythe electromagnet I22, the valve I24 being contained in a chamber I25which is in constant communication with the chamber I02 through apassage I26.

When the electromagnet I22 of the magnet valve device I23 isdeenergized, the double beat valve I24 is moved into seated relation ona valve seat I21 to close off the communication between chamber I25 andan atmospheric chamber I28, and is simultaneously unseated from a valveseat I34 to open communication between chamber I 25 and a chamber I29which is in constant communication with the chamber 95 of the magnetvalve device 88 through a passage I3I.

A coil spring I32, disposed in the chamber I29 and interposed between acollar secured to a fluted stem ofthe valve I24, and a screw plug I33closing the chamber I29, urges the valve I24 into seated relation on thevalve seat I21.

When the electromagnet I22 is energized, the double beat valve I24 ismoved against the force of spring I32 into seated relation on the valveseat I 34 to cut ofi communication between chamber I29 and chamber I25,and is simultaneously unseated from the valve seat I21 to opencommunication between the chamber I25 and the atmospheric chamber I28.

The electromagnets 90 and I22 of the magnet valve devices 88 and I23respectively, are adapted to be supplied with energizing current from asuitable source, such as a battery I36 carried on the train, in a mannerspecifically described hereinafter, under the control of the governordevice I9 and. the switch device 2 I.

The governor device I9 comprises a suitable casing I M adapted to bepivotally suspended from the floor I45 of the car on a pair of struts orlinks I42, only one of which is shown in Figure 2, the links I42 beingsecured at one end, to opposite ends of the casing I4I, respectively, asby bolts, rivets or welding, and pivotally suspended at the other end onlugs or pins I43 formed on or secured to an associated bracket I44 whichis suitably secured to the lower face of the car floor I45, as by boltsor screws, not shown.

The governor device I9 further comprises a rotary shaft I41 which issuitably mounted in a sleeve-like portion of the casing MI and whichprojects exteriorly of the casing, a pulley I48 being secured to theouter end of the shaft I41, which pulley is driven directly from asuitably proportioned pulley I49 mounted on a car wheel axle I56 throughthe medium of an endless belt II. If desired, the pulley I48 may bedriven in any other suitable manner in accordance with the speed of thetrain, as from a pulley mounted on the armature shaft of the usualgenerator carried on the train.

One of the supporting links I42 for the governor device I9 carriesthereon an insulated contact member I55 of the switch device 23, andwhen the belt I5I is properly positioned over the pulleys I 48 and I49,the contact member I55 engages a contact member I56 of the switch device23, which latter contact member is carried on a stem I51 slidablymounted in a bracket I58 carried in insulated depending relation on thefloor I45 of the car. A coil spring I59, interposed between the contactmember I56 and the bracket I58, yieldingly urges the contact member I56into engagement with the contact member I55 to close a circuittherethrough, which circuit will be hereinafter described.

A coil spring I 53 secured, at one end, to one of the supporting linksI42 of the governor device and at the other end, to a bracket I54secured in depending relation from the car floor I45 serves to tensionthe driving belt I 5| and also to separate the contact members I55 and I56 of the switch device 23 in the event of breakage of the belt I5I orin the event that the belt I5I is disengaged from the pulleys I 48 andI49.

A pair of stop brackets or lugs I6I, only one of which is shown, suitabysecured to the floor of the car or formed on the brackets I44 areadapted to be engaged by the links I 42, respectively, to

limit the movement of the governor device I9 by the spring I53.

The inner end of the rotary shaft I41 of the governor device I9 extendsinto a chamber I62 in the casing MI and has mounted thereon a pluralityof fiy-ball weighted levers I63, pivoted on suitable pins I64 andadapted to move radially outwardly in accordance with the speed ofrotation of the shaft I41. The inner ends of the weighted levers I63 areadapted to cooperate with a collar I65 formed on or secured to a switchactuating stem I66. A coil spring I61, interposed between the casing MIand the collar I65, yieldingly resists longitudinal movement of the stemI65 as the weighted levers move outwardly with increasing speed ofrotation of the shaft I41. The stem I66 extends into a chamber I68 inthe casing MI and has a contact bridging member I69 carried in insulatedrelation thereon, as hereinafter described, within the chamber I68.

When the speed of the train, and consequently the speed of rotation ofthe shaft I41 is less than a certain degree, such as that correspondingto ten or fifteen miles per hour, the spring I61 moves the stem I66longitudinally to cause the bridging member I69 to engage and connect apair of spaced contact members HI and I12 mounted in insulated relationupon the casing within the chamber I68. The contact bridging member I69is carried on an insulating block I13 which is slidably mounted on areduced portion of the stem I66 between spaced collars I14 and I15, anda pair of springs I16 and I11 interposed, respectively, between theblock I13 and the collar I14, and between the block I13 and the collarI15, serve to position the contact bridging member I69 centrally betweenthe collars I14 and I15. When the contact bridging member I69 is urgedinto contact with the contact members HI and I 12 as just previouslydescribed, the spring I16 yieldingly permits movement of the bridgingmember I69 relative to the stem I66 to limit the pressure on the contactmembers HI and I12 and accordingly decrease the stress and wear on theparts.

As the speed of the train increases, the weighted levers I63 on theshaft I41 on the governor device I9 move outwardly and causelongitudinal movement of the stem I66, against the force of the springI61, so that the contact bridging member I69 disengages the contactmembers HI and I12. When the speed of the train exceeds a predetermineddegree such as, for example, sixty miles an hour, the weighted leversI63 have moved outwardly a suflicient degree to cause the contactbridging member I69 to engage and connect a second set of spaced contactmembers I18 and I 8| mounted in insulated relation on the casing I Mwithin the chamber I68. Upon the engagement of contact bridging memberI69 with the contact members I19 and I 8|, the spring I 11 yieldinglypermits movement of the bridging member I69 relative to the stem I66 forthe same reason as does the spring I16.

The fluid pressure operated switch device 2I may be of any suitableconstruction and is illustrated as comprising a casing I85 containing apiston I86, the piston having a chamber I 81 at one side and a chamberI81a at the other side, which is closed by a cover plate I90. The pistonis adapted to operate three movable contact members I88, I89, and I9Ithrough the medium of a stem I92. A coil spring I93 disposed in chamberI81 and interposed between the casing I85 and the piston I86, serves toreturn the piston I86 to a position in which the movable contact membersI88, I89, and I9I are in circuit-opening position.

When fluid under pressure is supplied to the brake cylinder I6 throughpipe 32, fluid under pressure is simultaneously supplied to chamber |81aat one side of the piston I86 through a branch of brake cylinder pipe 32and causes the piston I86 to be moved against the force of the springI93, to a position such that the contact members I88, I89, and |9I arein circuit-closing position, in which position the contact membersremain as long as the fluid pressure overcomes the relatively lowtension of spring I93.

The circuit-maintaining relay 22is of the selfholding type and comprisesan electromagnet coil I and a movable armature I96, which is actuatedthereby to circuit-closing position in engagement with a. contact memberI91 upon energization of the coil I95, and which disengages the contactmember I91 upon deenergization of the coil I95.

The governor device I9, the fluid pressure operated switch device 2|,the circuit-maintaining relay 22, and the switch device 23 having nowbeen described, the circuit connections between the battery I36 and theelectromagnets of the magnet valve devices 88 and I23 may now bedescribed. The contact member I56 of the switch device 23 is connectedby a flexible conductor I98 to one terminal of the battery I36, theother terminal of which is grounded at I39, and the contact member I55of the switch device 23 is connected by a conductor I99 to both of thecontact members I12 and |8| of the governor device I9. Inthecircuit-closing position of the fluid pres- .sure operated switch 2|,contact member I88 thereof connects the electromagnet 98 of the magnetdevice 88 and the coil I95 of the circuitmaintaining relay 22 in seriesrelation in a circuit extending from the contact member I19 to theground at I38. If the contact bridging member I69 connects contactmembers I19 and I8I, the electromagnet 98 of the magnet valve device 88and the coil I95 of the relay 22 are energized. In ,the circuit-closingposition thereof, the contact member I89 of the switchdevice 2| connectsa wire 285 leading to the non-grounded terminal of the battery I36directly to a wire 284 leading to the contact member I91 of relay 22,and with the coil of relay 22 energized, the armature I96 connects thecontact member I91 to the battery-side terminal of coil I95 of relay 22,so that a shunt circuit is established around the governor device I9 formaintaining the coil of relay 22 and electromagnet 98 energizedindependently of whether or not the bridging member I69 connects contactmembers I19 and |8| of the governor device I9. Thus, once the coil ofrelay 22 is energized, it remains energized to maintain a circuit forenergizing electromagnet 98 of magnet valve device 88, notwithstandingthe disengagement of the contact bridging member I69 from the contactmembers I19 and I8I, as long as the switch device 2| remains incircuit-closing position. The reason for this circuit maintainingfeature will be made apparent hereinafter.

With the switch device 2| in circuit-closing position, the contactmember |9| thereof connects one terminal of the electromagnet I22 of themagnet valve device I23 to the contact member |1| of the governor deviceI9, through conductors 28| and 282. The other terminal of electromagnetcoil I22 is connected to ground at I38 and thus, if the switch device 2|is in circuitclosing position and the contact bridging member I69connects contact members HI and I12, the electromagnet coil I22 of themagnet valve device I23 is energized.

In operation, the brake pipe I I is charged with fluid under pressure inthe usual manner under the control of the usual brake valve device, notshown, and the auxiliary reservoir I2, the service reservoir I3, and theemergency reservoir I4 are also accordingly charged with fluid underpressure from the brake pipe I I through the medium of the brakecontrolling valve device I5 in the usual manner. In the charging orrelease position of the valve device I5 the brake cylinder port thereof,to which the pipe 33 and pipe 82 are connected, is in communication withthe atmosphere through the valve device I5 in the usual manner, and thusthe brake cylinder I6 and chamber I81a of switch device 2| are connectedto atmosphere. The chambers 12 and I82 at one side of the valve pistons1| and I8I, respectively, are charged with fluid under pressure from theemergency reservoir I4 through pipe 96 and past the valves 89 and I24 ofthe magnet valve devices 88 and I23, respectively.

Assuming that the train is running along the road at a speed, such asone hundred miles an hour, wherein the contact bridging member I69 ofthe governor device I9 connects the contact members I19 and I8I, andthat it is desired to eliect an emergency application of the brakes onthe train, a reduction in brake pipe pressure at an emergency rate ismade in the usual manner by means of the brake valve device, not shown.The brake controlling valve device I5 then functions in the usualmanner, in response to the reduction in brake pipe pressure at anemergency rate to supply fluid under pressure, first from the auxiliaryreservoir I2 and service reservoir I3 and then from the emergencyreservoir I4 to the brake cylinder I6, through pipes 33 and 32, chamber3|, past the valve 29, through passage 31, chamber 48, port 52, passages49 and 5|, chamber 54, past the unseated valve 53, through passage 56,and passage and pipe 51. Simultaneously, fluid under pressure suppliedinto the pipe 32 acts in chamber |81a on the piston I86 of the switchdevice 2| and causes actuation of the contact members I88, I89, and |9|to circuit-closing position.

The circuit for energizing the electromagnet 98 of the magnet valvedevice 88 and the coil I95 of the circuit-maintaining relay 22 is thuscompleted, as previously explained, and the double beat valve 89 of themagnet valve device 88 is actuated to close off the supply of fluidunder pressure from the emergency reservoir I4 to the chamber 12 and tovent the chamber 12 to atmosphere through passage 92, chamber 9| andatmospheric chamber 94. The actuation of the armature I96 of the relay22 into engagement with the contact member I91, caused by energizationof the coil of the relay 22, establishes the holding circuit, previouslydescribed, for maintaining the electromagnet 98 energized. Thus as thespeed of the train decreases below the predetermined speed of sixtymiles an hour, and the contact bridging member I69 accordinglydisengages the contact members I19 and I8I, the electromagnet 98 of themagnet valve device 88 remains energized and the chamber 12 at the oneside of the valve piston 1| accordingly remains vented as long as theswitch device 2| remains in circuit-closing position.

The fluid under pressure supplied through pipe 32, chamber 3| andpassage 86, and acting on the inner seated area of the valve piston 1|in the chamber 13, now overcomes the tension of the spring 18 andunseats the valve piston 1| from the annular rib seat 15. Since the faceof the valve piston II is larger than the inner seated area thereof whenseated on the annular rib seat 15, the valve piston is snapped orshifted suddenly and positively to the position in which the annular rib16 thereon seals against the gasket 11, to prevent leakage of fluidunder pressure to atmosphere past the valve piston from the chamber 13.In moving to the position just described, the valve piston 1| unseatsthe Valve 8| from the annular rib seat 82, and thus fluid under pressureis supplied from the chamber 3| through passage 86, chamber 13, past theannular rib seat 82, and into passage 5|, simultaneously with the supplythrough the communication, previously described, past the valve 29 andthrough passage 49.

The tension of the spring 4| acting on the piston 38 of the inshot valvedevice 28 is such that when the pressure in the brake cylinder attains aI predetermined degree, such as seventy-five pounds per square inch,which may correspond to the normal maximum braking ratio of one hundredand fifty per cent effected by the usual brake equipment including valvedevice I5 and standard capacity reservoirs I2, I3 and I4, the piston 38is moved downwardly against the force of the spring 4| by the pressureof the fluid supplied through the passage 31 in the collar 35, and thevalve 29 is thus lowered by gravity following the retraction of stem 36into seating engagement on the annular rib seat 34, to cut off thesupply of fluid under pressure to the brake cylinder by Way of passage49.

As previously indicated, the capacity of the emergency reservoir I4 isgreater than that of the standard emergency reservoir and is soproportioned relative to the capacity of the brake cylinder I6 that themaximum pressure attainable in the brake cylinder I6, which is the finalressure of equalization of the emergency reservoir and the brakecylinder, is a value, such as one hundred pounds per square inchpressure which may correspond to, for example, a two hundred per centbraking ratio. Since the valve piston 1| is maintained unseated from theannular rib seat 15 by the pressure of the fluid supplied to the brakecylinder, fluid continues to be supplied to the brake cylinder I6 untilthe maximum pressure is attained in the brake cylinder.

The brake shoes, not shown, are thus applied to the car Wheels with aforce for effecting a two hundred per cent braking ratio until the speedof the train has decreased to a low degree such as ten or fifteen milesan hour, wherein the contact bridging member I69 of the governor deviceI9 connects the contact members I 1| and I12, whereupon theelectromagnet 22 of the magnet valve device |23 is energized through thecircuit extending from one terminal of the battery I36 through conductorI98, switch 23, conductor I99, contact member I12, bridging member I69,contact member I 1!, conductor 202, movable contact member |9| of theswitch device 2|, conductor 26| and through electromagnet I22 of themagnet valve device I23 to ground at I38.

The valve I24 of the magnet valve device I23 is thus actuated to cut offthe supply of fluid under pressure from the emergency reservoir I4 tothe chamber I02 at one side of the valve piston and to establish acommunication, through passage I26, chamber I25 and atmospheric chamberI28, through which the fluid in the chamber I02 is vented. Brakecylinder pressure, acting through pipe and passage 51 and passage on theinner seated area of the valve I I0 in the valve piston |8I is thuseffective to raise the valve piston |0| away from the annular rib seatI05. In view of the fact that the face of the valve piston |0| is largerthan the inner seated area thereof, the valve piston is shifted suddenlyand positively into the position in which the annular rib I06 thereonengages the sealing gasket I01. The valve piston IOI, in moving to theposition just described, carries the valve ||0 away from the annular ribseat I I I and holds it unseated a sufficient distance to permit thespring 59 to seat the valve 53 on the annular rib seat 55. Thus,communication between the supply passage 5| and the passage 51 leadingto the brake cylinder I6 is out off by the valve 53 simultaneously withthe connection of the passage 51 to the blow-down valve I I1, past theunseated valve I I0 and through the chamber I03 and passage I I8.

The blow-down valve 1 is adjusted to permit the release of fluid fromthe brake cylinder until the pressure has been reduced to a value, suchas fifty pounds per square inch, corresponding to, for example, a onehundred per cent braking ratio.

Thus, when the train has been decelerated to a relatively low speed suchas fifteen miles per hour, the pressure in the brake cylinder I6 isrelieved through the blow-down valve 1 and the braking ratio isaccordingly reduced to a degree sufficient to bring the train to asmooth stop with no disagreeable shock or jar to the cars or passengers,and without sliding of the wheels.

If it is desired to release the brakes, after an emergency applicationof the brakes effected as just described, the brake pipe pressure isincreased in the usual manner by operation of the brake valve device,not-shown, and the brake controlling valve device I5 is accordinglyconditioned to recharge the auxiliary reservoir I2, the servicereservoir I3 and the emergency reservoir I4 in the usual manner and atthe same time establishes communication through which the pipe 32,leading to the brake cylinder and switch device 2|, is connected toatmosphere. Since the cut-01f valve 53 is seated on the rib seat 55 aslong as the valve piston |0| is unseated from the annular rib seat I05by the brake cylinder pressure, fluid under pressure cannot be releasedpast valve 53 but is vented from the brake cylinder I6 through theby-pass communication around the valve 53, that is, through passages 62and 63, past the check valve 61, and through passage 58 to chamber 54,whence it flows through passage 5|, chamber 13, passage 86 and pipe 32.Since the, brake cylinder pressure was reduced through the blow-downvalve M1 to a. degree below that at which the piston 38 of the inshotvalve device 28 is actuated to cause seating of the valve 29, the valve29 is unseated at this time and consequently fluid under pressure isalso vented from the passage 5| through passage 49, chamber 48, passage31, chamber 3| and pipe 32.

Fluid under pressure is thus completely vented from the brake cylinderI6 and from the chamber |81a of the switch device 2|, which resultsrespectively, in the complete release of the brakes and the movement ofthe contact members I88, I89, and |9| of the switch device 2| tocircuitopening position. The circuits for energizing the electromagnetsof the magnet valve devices 88 and I23 are thus interrupted, and themagnet valve devices are thus returned to the positions shown in Figure1, wherein fluid under pressure is again supplied to the chambers I2 andI02 at one side of the valve pistons 'II and IIJI, respectively, fromthe emergency reservoir I4, as previously described.

If an emergency application of the brakes is initiated when the train istraveling at a speed, such as forty-five miles per hour, which is lessthan that sufficient to cause the contact bridging member I69 of thegovernor device I9 to engage the contact members I19 and I8I, fluidunder pressure is supplied to the brake cylinder I6, as previouslydescribed, except that no fluid flows from the chamber 3I to the passage5| past the valve 8I in the valve piston II, because the pressure of thefluid in the chamber I2 is maintained due to the continueddeenergization of electromagnet of magnet valve device 88, the valvepiston II and the valve 8| being held seated on their respective ribseats against the force of the fluid under pressure supplied to thebrake cylinder.

Accordingly, the supply of fluid under pressure to the brake cylinder iscut off, due to the seating of the valve 29 on the valve seat 34, whenthe degree of brake cylinder pressure attained is sufficient to move thepiston 38 downwardly against the tension of the spring 4I. As previouslystated, the tension of the spring 4| is such that the valve 29 is seatedwhen the brake cylinder pressure attains a degree, such as seventyfivepounds per square inch, corresponding to the maximum brake cylinderpressure attainable with present standard passenger car brake equipment.

Thus, it will be seen that for emergency applications of the brakesinitiated at a time when the train speed is less than a predeterminedhigh speed, such as sixty miles per hour, the usual maximum brakingratio of one hundred and fifty per cent effected by present standardbrake equipment on passenger cars is obtained.

As in the previously described emergency application of the brakes, whenthe speed of a train decreases to the point where the contact bridgingmember I69 of the governor device I9 engages and connects the contactmembers HI and H2, the electromagnet I22 of the magnet valve device I23is energized and the double beat valve I24 is accordingly actuated tothe position for venting the chamber I02 at the one side of the valvepiston IOI to atmosphere. As in the previously described emergencyoperation, the vent ing of the chamber I02 at the one side of the valvepiston IUI effects the simultaneous actuation of the cut-off valve 53and the valve III], to respectively cut off the supply communication tothe brake cylinder passage 51 and to open the passage 51 to theblow-down valve I I1. Thus, brake cylinder pressure is reduced to thedegree determined by the setting of the blow-down valve I I! to attainthe lower braking ratio at the lower speeds to prevent wheel sliding.

Release of the brakes, following an emergency application of the brakesinitiated at a time when the train is traveling at a speed less than thepredetermined high speed of sixty miles an hour, is effected in the samemanner as previously described, by increasing the brake pipe pressurethrough the medium of the usual brake valve device, not shown, tocondition the brake controlling valve device I5 in release or chargingposition.

Since the electromagnet 90 of the magnet valve device 88 was notenergized, due to the fact that the train was not traveling at asuflicient speed to cause the governor device I9 to close the circuitfor energizing the electromagnet 99 of the magnet valve device 88, andsince the valve piston II accordingly remained seated on the annular ribseat I5, fluid under pressure is released from the brake cylinder toatmosphere, under control of valve device I5, as in the previouslydescribed operation, except that the passage 5I is in communication withthe pipe 32 only past the unseated valve 29 of the inshot valve device28.

If the belt I5I associated with pulley I48 of the governor device I9breaks, or if the belt I5I disengages the pulleys I48 and I49, thegovernor device I9 is accordingly rendered inoperative and the springI53 acts to open the switch device 23. Thus, the circuits for energizingthe electromagnets of the magnet valve devices 88 and I23 areinterrupted, and therefore, upon the initiation of an emergencyapplication of the brakes, fluid under pressure is supplied to the brakecylinder I6 under the sole regulation of the inshot valve device 28, themaximum pressure attained in the brake cylinder being thus determined bythe adjustment of the inshot valve device 28, as in the case of anemergency application of the brakes initiated at the time the train istraveling at a speed less than the predetermined high speed of sixtymiles per hour.

Since the circuit for energizing the electromagnet I22 of the magnetvalve device I23 is interrupted, due to the opening of the switch device23, the chamber I02 at one side of the valve piston I9I will not bevented at the time the train speed decreases to a relatively low speed,such as ten or fifteen miles per hour, and consequently no reduction inthe brake cylinder pressure through the blow-down valve ill will occur.

It will thus be seen that in the event of the breakage of the pulleybelt I5I or disengagement of the belt from the pulleys, the brakecontrol equipment operates as does present standard passenger car brakeequipment, to effect approximately a one hundred and fifty per centbraking ratio during the entire time the emergency application of thebrakes is being effected. As previously noted, however, a one hundredand fifty per cent braking ratio is sufficiently low not to cause animmoderate amount of wheel sliding. The difference in braking action,due to the failure to reduce the brake cylinder pressure to the degreedetermined by the blow-down valve 1 at the time that the speed of thetrain is reduced to a relatively low speed, will indicate to theengineman that the governor device I9 is inoperative and he may thentake steps to remedy this condition.

It should be understood that upon service applications of the brakes,the valve mechanism I8 and associated supplemental equipment providedaccording to our invention, is inoperative to effect a braking ratiohigher than the usual braking ratio effected by standard passenger carbrake control equipment, for service applications of the brakes.

It will be apparent that such is the case because, as is well known, theusual safety valve 291 provided on the brake controlling valve device I5is effective upon the conditioning of the valve device I5 to effect aservice application of the brakes, to limit the brake cylinder pressureto a maximum degree such as sixty-three pounds per square inch, whichpressure is less than the pressure required to effect closing of thevalve 29 of the inshot valve device 28 embodied in the supplementalvalve mechanism !8. Consequently, since the brake cylinder pressure islimited, in service applications, by the setting of the safety valve281, valve mechanism !8 cannot perate to effect a brake cylinderpressure and accordingly higher braking ratio, than is eifected bypresent standard brake equipment.

The valve mechanism I 8 is operative, however, in the event of a fullservice application of the brakes having been effected and a brakecylinder pressure, such as sixty-three pounds per square inch, which isin excess of the setting of the blow-down valve H1, having beenattained. In such case, when the speed of the train decreases to thepredetermined low speed, such as ten or fifteen miles per hour, at whichthe contact bridging member I69 of the governor device !9 connects thecontact members l1! and I12 and completes the circuit for energizing theelectromagnet 122 of the magnet valve device I23, chamber I02 at oneside of the valve piston I8! is vented, as in an emergency applicationof the brakes, and the reduction in brake cylinder pressure to thedegree determined by the blowdown valve H1 effected, as previouslydescribed for emergency applications of the brakes.

Referring to Figure 3, the embodiment of our invention disclosed thereindiffers from that shown in Figures 1 and 2 in the provision of adifferent type of valve mechanism in place of the valve mechanism I8shown inFigure 1. As shown in Figure 3, the valve mechanism employed inplace of the valve mechanism !8, includes a valve device 2!! and amagnet valve device 2|2. The valve device 2!! comprises three movableabutments or diaphragms 2l4, 215, and 2I6 suitably mounted in spacedcoaxial relation between the separate sections of the casing 2l1, andsecured to a stem 218 which is slidably supported in the casing. Thediaphragms 2 l4, 2I5, and 2 l6 decrease successively in area, accordingto principles hereinafter set forth, the diaphragm 2! 4 being larger inarea than the diaphragm 2!5, and the diaphragm 2!5 being larger in areathan the diaphragm 216.

At one side of diaphragm 2l4 is a chamber 2!!! having a reduced portion22! in which operates a loose fitting guiding piston 222 formed on orsecured to the stem 2!8. Between the diaphragms 2! and 2!5 is a chamber223, and between the diaphragms 2|5 and 2 I6 is a chamber 224. Betweenthe diaphragm 216 and the casing is a chamber 225 in which is disposed abiasing means, such as a coil spring 226, which is interposed betweenthe diaphragm 2!6 and the casing and which normally urges all thediaphragms, through the medium of stem 2 !8, toward the left handdirection, as viewed in Figure 3, to cause the left end of the stem toengage and unseat a supply valve 221 from an annular rib seat 228. Thesupply valve 221 is adapted to control com munication through a passage234, between a chamber 229, which is in constant communication with thebrake cylinder port of the brake controlling valve device [5 through apipe 23!, and a chamber 232 which is connected to the brake cylinder !6through a pipe 233 and to chamber 225 through a pipe 266.

The valve 221 is in the form of a valve piston and is slidably mountedin a bore or chamber 238 in a screw plug 220, which closes the open endof chamber 229, a return spring 261 of relatively light tension beinginterposed in the chamber 230 between the valve 221 and plug 220, forurging the valve toward seated relation on the rib seat 228. Means, suchas a port 256 through valve 221 or grooves in the peripheral surface ofthe valve, is provided in order to prevent dashpot action of valve 221in the chamber 238 and to establish communication between chamber 229and chamber 230 on opposite sides of the valve 221 and thereby soequalize the fluid pressures thereon as to permit spring 261 to beeffective to hold the valve 221 seated on the rib seat 228, as will bedescribed hereinafter.

An exhaust slide valve 235, which has limited loose movement betweenspaced shoulders 236 and 231 on the stem 218, is provided in the chamber232, the valve 235 normally covering an atmospheric port 238, and beingadapted to be moved by the stem for controlling the exhaust of fluidunder pressure from the brake cylinder !6 and chamber 232, through theatmospheric exhaust port 238.

The magnet valve device 212 comprises a pair of valve devices 239 and246 having electromagnets 24! and 242, respectively, which arecontrolled in the same manner as are the electromagnets of valve devices88 and I23, respectively, by means of governor device !9 and switchdevice 2 I.

The magnet valve device 239 comprises a pair of oppositely seatingvalves 243 and 244, connected by a fluted stem 245 and disposed,respectively, in an atmospheric chamber 246 and a chamber 241. A spring248, disposed in the chamber 241 and interposed between valve 244 and ascrew plug 280 which closes the chamber 241, yieldingly urges the valves243 and 244 in a direction such that the valve 243 is normally unseatedand the valve 244 is seated. Intermediate the chambers 246 and 241 is achamber 249 which is in constant communication with the chamber 223,between the diaphragms 2 I 4 and 2 l 5, through a pipe or conduit 25!.Normally, chamber 249 is in communication with the atmospheric chamber245 past the unseated valve 243 and is cut off from chamber 241 by valve244. Energization of electromagnet 24! causes the valves 243 and 244 tobe shifted to seated and unseated positions, respectively, to out offcommunication between chambers 249 and 246, and open communicationbetween chambers 249 and 241.

The magnet valve device 240 comprises a double beat valve 253 having afluted stem 254, the valve 253 being disposed in a chamber 255 which isin constant communication with the chamber 224, between the diaphragms 2l 5 and 2 I 6, through a pipe or conduit 256. A spring 251, disposed ina chamber 258 into which the fluted stem 254 extends, is interposedbetween a collar on the end of the stem 254, and a screw plug 259closing the chamber 258, for urging the double beat valve 253 to aposition such that it establishes communication between the chamber 255and the chamber 258, and closes communication between chamber 255 and anatmospheric chamber 265. Upon energization of electromagnet 24!, thevalve 253 is shifted to establish communication between chamber 255 andatmospheric chamber 255, and to cut oii communication between chambers255 and 258.

The chamber 241 of the magnet valve device 239 and the chamber 258 ofthe magnet valve device 240 are connected by a passage 26!, which is incommunication with the pipe 233 leading to the brake cylinder I6,through a pipe and passage 262 and a branch pipe 263.

The pipe 262 is connected to the switch device 2| and fluid underpressure is supplied there through from brake cylinder pipe 233 to causeactuation of the switch contact members I88, I89, and I9! tocircuit-closing position.

In operation, the brake pipe II is charged with fluid under pressure bymeans of the usual brake valve device, not shown, and the brakecontrolling valve device I5 is accordingly conditioned in charging orrelease position to charge the auxiliary reservoir I2, the servicereservoir l3, and the emergency reservoir I4 in the usual manner, whileestablishing communication therethrough from the brake cylinder supplypipe 23I to atmosphere.

If an emergency application of the brakes is initiated, in the usualmanner, by effecting a reduction in brake pipe pressure at an emergencyrate, while the train is traveling at a speed, such as one hundred milesper hour, the brake controlling valve device I5 is operated, in theusual manner, to supply fluid under pressure, first, from the auxiliaryreservoir I2 and service reservoir I3, and then from the emergencyreservoir I4 to the brake cylinder I6, through pipe 23I, chamber 229,past the unseated supply valve 221, through passage 234, chamber 232 andpipe 233.

At the same time, fluid under pressure is supplied from pipe 233 to theswitch device 2|, through branch pipe 263 and pipe 262 to effectactuation of switch contact members I88, I89 and I9I of the switchdevice 2| to circuit-closing position, fluid under pressure being alsosupplied to the chamber 224, between the diaphragms 2 I5 and 2I6,through pipe and passage 262, passage 26I, chamber 258, past valve 253,through chamber 255 and pipe 256.

Fluid under pressure is also supplied from the slide valve chamber 232of controlling valve device 2II to the chamber 225 through pipe 266.Also, due to the fact that the train is traveling at a speed of onehundred miles per hour which is in excess of the predetermined highspeed of sixty miles per hour, the circuit for energizing theelectromagnet 24I of the magnet valve device 239 is completed throughthe governor device I9 and the magnet valve device 239 is accordinglyactuated to a position such that fluid is supplied from the pipe 262through passage 26I, chamber 241, past the unseated valve 244, chamber249, and pipe 25I to the chamber 223, between diaphragms 2I4 and 2I5.Since the piston 222 has only a loose fit in the chamber 22l, fluidunder pressure flows from the chamber 232 into the chamber 2I9, past thepiston 222.

Thus, all of the diaphragms 2I4, 2I5, and 2I6 are subjected on bothsides to the same increasing fluid pressure, and the biasing spring 226accordingly maintains the supply valve 221 unseated so that fluid issupplied to the brake cylinder I6 until the maximum pressure attainableis reached.

As explained above in connection with the embodiment shown in Figure 1,the emergency reservoir I4 is of greater capacity than the usualemergency reservoir employed in the standard passenger car brakeequipment and is so proportioned relative to the capacity of the brakecylinder I6 that a maximum brake cylinder pressure of, for example, onehundred pounds per square inch is attained, which may correspond to abraking ratio of two hundred per cent.

When the speed of the train is decreased under the effect of the twohundred per cent braking ratio to a relatively low speed, such as ten orfifteen miles per hour, at which the governor device l9 completes thecircuit for energizing the electromagnet 242 of the magnet valve device246, the chamber 224, between the diaphragms 2I5 and 2I6, is vented toatmosphere through pipe 256, chamber 255, past the double beat valve 253and through chamber 265. The differential force of the fluid pressure inchamber 223 acting on the diaphragm 2I5 and the fluid pressure in thechamber 225 acting on the diaphragm 2I6 accordingly becomes effective tocompress the biasing spring 226 and thereby cause shifting of the stem2I8 toward the right hand direction. The supply valve 221 is thuspermitted to be urged into seated relation on the rib seat 228 by thespring 261 to cut off communication between the chamber 229 and thechamber 232, following which the exhaust valve 235 is shifted to uncoverthe exhaust port 238.

Fluid under pressure is thus vented through port 238 simultaneously fromthe brake cylinder I6, chamber 225, chamber 223, and chamber 2I9, andwhen a suflicient reduction in brake cylinder pressure has been thusproduced, and the differential force of the fluid pressures acting onthe diaphragms 2I5 and 2I6 is insufficient to overcome the spring 226,the spring 226 acts to shift the stem 2I8 and accordingly the exhaustvalve 235 toward the left hand direction into lap position wherein theport 238 is closed to cut off further reduction in brake cylinderpressure, the stem 2I8 being shifted insufilciently to unseat supplyvalve 221 since further movement of the stem to the left is stopped assoon as reduction in brake cylinder pressure is stopped.

The relative areas of the diaphragms 2i5 and 2I6 are so designed thatwhen the diaphragms are subjected to a differential force occasioned bya fluid pressure, of for example, fifty pounds per square inch,corresponding to a braking ratio of about one hundred per cent, thereduction in brake cylinder pressure occasioned as a result of theventing of the chamber 224, is cut off as just described.

As in the embodiment shown in Figure 1, this reduction in brake cylinderpressure and in the braking ratio, when the train speed decreases to arelatively low degree, enables a smooth stop without shock anddiscomfort to the passengers and also prevents sliding of the wheels.

If it is desired to release the brakes following an emergencyapplication of the brakes effected in the manner just described, anincrease in the fluid pressure in the brake pipe II is effected in theusual manner by means of the brake valve device, not shown, the brakecontrolling valve device I5 being thereupon conditioned in release orcharging position wherein the auxiliary reservoir I2, the servicereservoir I3 and the emergency reservoir I4 are again charged with fluidunder pressure from the brake pipe I! in the usual manner, and the pipe23I leading to the brake cylinder I6 is connected, through the valvedevice I5, to atmosphere. The chamber 229 in the casing of the valvedevice 2I I and the chamber 230 at the back of the valve piston 221,which latter chamber is connected to the chamber 229 through the port250 in the valve piston, are thus connected to atmosphere, and when asuificient reduction in the fluid pressure has been made, the brakecylinder pressure and the pressure of fluid in the chamber 232 acting onthe inner seated area of the valve piston 221 in the passage 234 unseatsthe valve piston 22'! from the rib seat 223 against the force of thespring 261. Fluid under pressure is thus vented from the brake cylinderto atmosphere through pipe 233, chamber 232, passage 234, chamber 229,pipe 23! and the valve device l5.

Since the electromagnets 24| and 242 of the magnet valve devices 239 and240, respectively, remain energized as long as the switch device 2| isin circuit-closing position, the chambers and 224 in the valve device 2Hremain connected to the pipe 262 and to the atmospheric chamber 265,respectively. Thus, the pressure of the fluid in chamber 22% reducessimultaneously with that in the brake cylinder l6. Since chambers 2H]and 225 of the valve device 2|| are in constant communication with theslide valve chamber 232 of the valve device 2| I, the pressure of thefluid in these chambers also reduces simultaneously with that in thebrake cylinder it.

When the pressure of the fluid in chambers 223 and 225 has reducedsufficiently, the biasing spring 2225 becomes effective to shift thediaphragms and the stem 2|8 to the left, until the left end of the stemengages and maintainsthe valve piston 22? in unseated relation withrespect to the rib seat 228. Thus, since the spring 225 maintains thevalve piston 22'! unseated against the force of the spring 261, completeventing of the brake cylinder l6 and of the piston chamber in the switchdevice 2| is effected.

The brakes are thus completely released and the electromagnets 2M and 232 of the magnet valve devices 239 and 240, respectively, aredeenergized.

In the event that an emergency application of the brakes is initiated ata time when the train is traveling at a speed, such as forty-five milesan hour, which is less than the predetermined high speed of sixty milesper hour, the electromagnet 2d! of the magnet valve device 239 is notenergized, due to the fact that the circuit for energizing theelectromagnet is not completed through the governor device 9.Accordingly, the chamber 223, between the diaphragms 2M and H5, isvented to atmosphere through the pipe 25!, chamber 249, past theunseated valve 243 and through the atmospheric chamber 246. In otherrespects, fluid under pressure is supplied through the pipe 23| to thebrake cylinder it, the switch device 2| and to chambers 2|9, 224 and 225of the valve device 2, as in the previously described operation.

It will thus be clear that the differential force of the fluid pressureacting in chamber 2|9 on the diaphragm 2M and in chamber 224 on thediaphragm 2|5, exerts a force in opposition to the biasing spring 226tending to move the. diaphragms and the stem 2 It to the right, asViewed in Figure 3.

When the pressure of the fluid supplied through pipe 23! to the brakecylinder l5 attains a degree, such as seventy-five pounds per squareinch, corresponding substantially to a one hundred and fifty per centbraking ratio, the differential force of the pressures acting on thediaphragms 2M and 2 5 is sufficient to so compress the spring 226 andshift the stem and diaphragms in the right hand direction, as to permitseating of the valve piston 22! on the annular rib seat 228, to cut offthe further supply of fluid under pressure to the brake cylinder l6. Dueto the loose movement of the exhaust valve 235 between the shoulders 236and 23'! on the stem 218, the shifting of the stem 2 8 is insufiicientat this time to cause the valve 235 to uncover exhaust port 238.

When the speed of the train has decreased to a relatively low degree,such as ten or fifteen miles per hour, under the effect of the onehundred and fifty per cent braking ratio, the circuit for energizing theelectromagnet 262 of the magnet valve device 240 is completed, throughthe governor device I 9, as in the previously described operation, andthe double beat valve 253 of the magnet valve device 240 is accordinglyoperated to establish communication from the chamber 224, between thediaphragms M5 and HG, to the atmosphere, through pipe 256, chamber 255,and atmospheric chamber 265.

In view of the fact that the two chambers 223 and 224 are vented toatmosphere, the differential force of the fluid pressure in chamber 2|9acting on the diaphragm 2M and the fluid pres sure in chamber 225 actingon the diaphragm 2I6 becomes effective to further compress the spring225 and to cause shifting of the stem 2| 8 in the right hand directionto a degree such that the exhaust slide valve 235 uncovers the exhaustport 238. It will be apparent that the differential force effective asbetween diaphragms 2M and 2 i5 is greater than that effective as betweenthe diaphragms 2M and 2|5 for the same fluid pressure, since thediaphragm 2|6 is smaller in area than the diaphragm 2|5.

Fluid under pressure is thus released from the brake cylinder 6, theswitch device 2|, the chamber 259 and the chamber 225 through the port232, and when the difierential force of the fluid pressures acting onthe diaphragms 2M and H5 is reduced sufficiently, spring 226 acts toshift the stem 2 I8 and the diaphragms in the left hand direction tocause the exhaust slide valve 235 to lap or cover the exhaust port 233and cut off further reduction in brake cylinder pressure, withpositionwhen the brake cylinder pressure is reduced to substantially thirtypounds per square inch, that is, to a degree corresponding to a brakingratio of sixty per cent.

It will thus be seen that when the speed of the train is reduced to therelatively low speed of ten or fifteen miles per hour following anemergency application of the brakes initiated at the time the train wastraveling at a speed less than the predetermined high speed of sixtymiles an hour, the final braking ratio or brake cylinder pressure isless than the ratio or brake cylinder pressure effected when the speedof the train is reduced to ten or fifteen miles an hour following anemergency application of the brakes initiated at the time the train wastraveling at a speed in excess of the predetermined high speed of sixtymiles per hour.

The purpose of causing a lesser final braking ratio dependent uponwhether the emergency application of the brakes was initiated at a timethat the train was traveling at a speed in excess of or below apredetermined speed is to obtain substantially the same braking effectjust prior to the train being brought to a complete stop, regardless ofvariations in the coefficient of friction between the brake shoes andthe car wheels resulting from variations in the temperature thereofoccasioned by application of the brake shoes to the car wheels initiallyat relatively high speeds or initially at relatively low speeds. Asnoted hereinbefore, the heat generated in the brake shoes upon anapplication of the brakes at high speed greatly reduces. the coefficientof friction between the brake shoes and the car wheels and thus agreater braking force, that is, pressure of brake shoes against the carwheels, is necessary in order to obtain the same braking effect at thetime the brake cylinder pressure is relieved to prevent sliding of thewheels, in the case of an application of the brakes initiated at a timewhen the train is traveling at a high speed as compared to anapplication of the brakes initiated at the time the train is travelingat a lower speed.

Thus, in the embodiment of my invention shown in Figure 3, variations inthe coefficient of friction between the brake shoes and the car wheelsoccasioned by variations in the amount of heat developed in the brakeshoes are automatically compensated for and a higher final braking ratioor brake cylinder pressure produced when the train is brought to a stopfrom a relatively high speed as compared to when the train is brought toa stop from a relatively low speed.

Release of the brakes, following an emergency application of the brakesinitiated at the time the train is traveling at a speed less than thepredetermined high speed of sixty miles per hour, as just described, iseffected in the same manner as previously described for release of thebrakes following an emergency application of the brakes initiated at thetime the train is traveling at a speed in excess of the predeterminedhigh speed, and it is therefore deemed unnecessary to specificallydescribe this release operation.

The embodiment shown in Figure 4, differs from the embodiment shown inFigure 3 in providing a valve device 268 in place of the controllingvalve device 21!, the valve device 268 differing from the valve device2! l in having only two movable abutments or diaphragms 259 and 21!, oflarger and smaller area, respectively, suitably mounted in the casing ofthe valve device and secured to the operating stem 2l8 for controllingthe operation of the supply valve 221 and the exhaust valve 235 in amanner similar to that effected by the three diaphragms in theembodiment shown in Figure 3. While the diaphragms 269 and 21! appear tocorrespond in area, with that of the diaphragms 2M and 2E6,respectively, it should be understood that the proportions of thediaphragms 289 and 21! relatively to the diaphragms 2 l4 and H5 maydiffer. Furthermore, it should be understood that a biasing spring 226aof different tension may be employed instead of the biasing spring 226shown in the embodiment of Figure 3, although the two springs may beidentical.

In the embodiment of Figure 4 the pipe 25! leading from the chamber 249of the magnet valve device 239 is in constant communication with achamber 213 between the diaphragms 269 and 21!. Also, the pipe 256leading from cham ber 255 of magnet valve device 240 is connected to thechamber 225, there being no communication between chamber 225 andchamber 232, as through the pipe 266, shown in Figure 3.

The embodiment of Figure 4 differs from the embodiment of Figure 3 alsoin the provision of a blow-down or pressure valve 214 to which thechamber 265 of the magnet valve device 240 is connected through apassage 215. The blowdown valve 214 has a predetermined setting oradjustment for maintaining a predetermined pressure, the degree of whichand the reason for which will be made apparent hereinafter.

Assuming that the equipment has been charged in the manner describedpreviously in connection with the embodiment shown in Figure 3, and thatan emergency application of the brakes has been initiated in the mannerpreviously described, at the time that the train is traveling at aspeed, such as one hundred miles per hour, which is in excess of thepredetermined high speed of sixty miles per hour, fluid under pressureis supplied to the brake cylinder !6 through the supply pipe 23! leadingfrom the brake controlling valve device l5, through chamber 229, pastthe supply valve 221, which is held unseated by the spring 226a, throughthe passage 234, chamber 232 and pipe 233. Since the electromagnet 242of the magnet valve device 240 is deenergized, fluid under pressure issupplied from the pipe 233 to the chamber 225 at the right of diaphragm21! through pipe 263, the pipe and passage 262, passage 26!, chamber258, past the valve 253, through chamber 255 and pipe 256. Furthermore,since the electromagnet 24! of the magnet valve device 239 is energized,fluid under pressure is also supplied from the pipe 233 to the chamber213, between the diaphragms 269 and 21!, through the pipe 263, pipe andpassage Z62, passage 25 I, chamber 241, past the unseated valve 244,through chamber 249 and pipe 25!. As in the embodiment of Figure 3,fluid under pressure is also supplied from the chamber 232 to thechamber 256 at the left of the diaphragm 269 past the loose fittingpiston 222. Thus both the sides of the diaphragms. 269 and 21! aresubjected to the increasing brake cylinder pressure, so that the fluidpressure forces acting on the diaphragms are balanced. The spring 226ais therefore effective to maintain the supply valve 221 unseated untilthe maximum pressure, as determined by the individual and relativecapacities of the emergency reservoir and the brake cylinder isattained, which will effect a maximum braking ratio of, for example, twohundred per cent and corresponding to a brake cylinder pressure of onehundred pounds.

When the speed of the train has decreased to a relatively low speed,such as ten or fifteen miles per hour, governor device I9 is effective,as previously described, to complete the circuit for energizing theelectromagnet 242 of the magnet valve device 240, and the chamber 225 atthe right of the diaphragm 21! is accordingly connected to the blow-downvalve 214 through pipe 256, chamber 255, past valve 253, through chamber265, and passage 215, so that the pressure in chamber 225 is reduced tothe degree maintained by the blow-down valve 214.

The pressure of the fiuid in chamber 213 which corresponds to the brakecylinder pressure, acting on the left face of. the diaphragm 21! is thushigher than the combined force of the spring 2260!, and the reducedpressure in chamber 225, and consequently the diaphragms 269 and 21!, aswell as the stem 218, are shifted in the right hand direction to firstseat the supply valve 221 and then cause the exhaust valve 235 touncover the exhaust port 238. Fluid under pressure is accordinglyreleased from the brake cylinder IS, the chambers 2l9 and 213 of thevalve device 268, and the piston chamber of the switch device 2|,communication from the chamber 225 to chamber 258 and thus to the brakecylinder pipe 233 being cut off by the double beat valve 253 of themagnet valve device 249.

When the force of the brake cylinder pressure acting in the chamber 2%on the left face of. the diaphragm 2' is reduced sufficiently by thereduction in brake cylinder pressure, the spring 228a becomes effectiveto shift the stem 2l8 and diaphragms 269 and 2' in the left handdirection so that the exhaust valve 235 covers or laps the exhaust port238 without unseating the supply valve 227.

The pressure maintained in chamber 225 by the blow-down valve 215 issuch in relation to the tension characteristics of the spring 226a andthe area of the diaphragm 21!, that when the brake cylinder pressure isreduced to a value, such as fifty pounds, and corresponding to a onehundred per cent braking ratio, cut-off of the exhaust of fluid underpressure from the brake cylinder through the exhaust port 238 iseffected.

Thus before the train stops, the relatively high braking ratio of twohundred per cent is reduced to a braking ratio of one hundred per cent,and the train is brought to a stop smoothly and with no discomfort orshock to the passengers and without sliding of. the wheels.

The release of the brakes, following an emergency application of thebrakes, effected in the manner just described, is effected in the mannerpreviously described for the embodiment shown in Figure 3, and it isdeemed unnecessary, therefore, to specifically describe this operation.

In the embodiment shown in Figure 4, let it be assumed that while thetrain is traveling at a speed, such as forty-five miles per hour, whichis below the predetermined high speed of sixty miles per hour, emergencyapplication of the brakes is initiated in the manner previouslydescribed. In such case, the circuit for energizing the electromagnet24! of the magnet valve device 239 is not completed through the governordevice l9, and the chamber 2'53 between the diaphragms 259 and 21! isaccordingly connected to atmosphere through the pipe 251, chamber 249,past unseated valve 2&3, and through atmos pheric chamber 246. As in theemergency application of the brakes previously described for theembodiment shown in Figure 4, fluid under pressure is supplied to thebrake cylinder Hi, the switch device 2 l, the chamber 225, and thechamber 2H9. In view of the fact that the chamber 2'33 is at atmosphericpressure, it will be apparent that as the brake cylinder pressureincreases and as. the differential force of the fluid pressure acting inchamber 219 on the diaphragm 259 and the fluid pressure in the chamber225 acting on the diaphragm 2'?! increases sufficiently to overcome thetension of the spring 226a, the diaphragms and the stem ZIB will beshifted in the right hand direction sufficiently to seat the supplyvalve 22'i and cut oif the further supply to the brake cylinder, withoutshifting the exhaust valve 235 to uncover the exhaust port 238.

The relation of the areas of the diaphragms 259 and 2H and the tensioncharacteristics of the spring 225a are such, that when the brakecylinder pressure and accordingly the pressure of the fluid in chambers259 and 225 attains a degree, such as seventy-five pounds per squareinch, and corresponding to a braking ratio of one hundred and fifty percent, the further supply of fluid under pressure to the brake cylinderI6 is cut off by seating of supply valve 221. It will thus be seen thatwhen an emergency application of. the brakes is initiated at a time thatthe train is traveling at a speed less than the predetermined high speedof sixty miles per hour, the braking ratio attained is. one hundred andfifty per cent as compared to the maximum braking ratio of two hundredper cent attained when an emergency application of the brakes isinitiated at a time that the train is traveling at a speed in excess ofthe predetermined high speed of sixty miles per hour.

The train is thus decelerated under a braking ratio of one hundred andfifty per cent until a relatively low speed such as ten or fifteen milesper hour is reached, at which time governor device l9 completes thecircuit for energizing the electromagnet 242 of the magnet valve device240.

The magnet valve device 240 is thus actuated, as previously described,to establish communication from the chamber 225 to the blow-down valve274, and the pressure of. the fluid in the chamber 225 is accordinglyreduced to the degree determined by the blow-down valve 214.

The differential force of the brake cylinder pressure acting in chamber2 IS on the diaphragm 269 and the reduced fluid pressure in chamber 225acting on the diaphragm 21! thus becomes effective to further overcomethe tension of the spring 226a, and the diaphragms and the stem 2l8 areaccordingly shifted in the right hand direction sufficiently to causethe exhaust valve 235 to uncover the exhaust port 238. Fluid underpressure is accordingly vented from the brake cylinder l6 and chamber2l9 through the exhaust port 238 until the pressure of the fluid isreduced to a degree insufiicient to overcome the combined force of thetension of the spring 226a and the reduced fluid pressure acting inchamber 225 on the diaphragm 21!, at which time the spring 226a becomeseffective to shift the diaphragm and the stem 2i8 in the left handdirection sufficiently to cause the exhaust valve 235 to cover or lapthe exhaust port 238, further reduction in brake cylinder pressure andof the pressure in chamber 2I9 being thereby cut off. Consequently,further movement of the diaphragm and the stem in the left handdirection is immediately stopped and unseating of the supply valve 227is therefore not effected. The reduced pressure in the brake cylinder isthus maintained until the train is completely stopped.

As in the previously described emergency application of the brakes forthe embodiment shown in Figure 4, the train is accordingly brought to asmooth stop without shock or discomfort to the passengers and withoutsliding of the wheels. 7

It should be noted that the degree to which the brake cylinder pressureis reduced at the time the train speed is reduced to ten or fifteenmiles per hour, following an emergency application of the brakesinitiated at a time that the train speed was less than the predeterminedhigh speed of sixty miles per hour, is less than the degree to which thebrake cylinder pressure is reduced at the time the speed of the train isreduced to ten or fifteen miles per hour, following an emergencyapplication of the brakes initiated at a time that the train wastraveling at a speed in excess of the predetermined high speed of sixtymiles per hour. Obviously, the degree to which brake cylinder pressureis reduced in the two cases is determined according to the relativeareas of the diaphragms 269 and 21!, the ratio of brake cylinderpressures in the two cases being in inverse proportion to the ratio ofthe areas of the diaphragms on which the fluid pressure acts.

Thus the embodiment shown in Figure 4 is adapted to automaticallycompensate or differentiate as to the final brake cylinder pressure, ina manner similar to the embodiment shown in Figure 3, depending upon thespeed with which the train was traveling at the time the emergencyapplication of the brakes was initiated, allowance for variations in thecoeffiacient of friction between the brake shoes and the car wheels,occasioned by variations in the heat developed in the brake shoes, beingaccordingly automatically effected.

Release of the brakes, following an emergency application of the brakesinitiated at the time the train is traveling at a speed less than thepredetermined high speed of sixty miles per hour, in the embodimentshown in Figure 4, being similar to that described for the embodimentshown in Figure 3, it is deemed unnecessary to specifically describethis operation.

As is the case in the embodiment shown in Figure 1, wherein thesupplemental valve mechanism I8 is inoperative to effect a braking ratiohigher than the usual braking ratio effected by the standard passengercar brake control equipment for service applications of the brakes, soalso are the valve devices 2 and 268, of the embodiments shown inFigures 3 and 4 respectively, inoperative to efiect a braking ratiohigher than the usual braking ratio for service applications of thebrakes, effected by standard passenger car brake control equipment. Itwill be apparent that such is the case because the springs 2253 and 225aof the valve devices 2 and 268, respectively, are so tensioned as tomaintain the supply valve 22! unseated until a brake cylinder pressureof at least seventy-five pounds per square inch has been attained uponan application or" the brakes. Since, as previously explained inconnection with the embodiment shown in Figure 1, the safety valve 20'!associated with the brake controlling valve device l5 functions during aservice application of the brakes to limit the brake cylinder pressureto a maximum degree of sixty-three pounds per square inch, it followsthat whether the service application of the brakes is initiated at thetime the train is traveling at a speed in excess of or below thepredetermined high speed of sixty miles per hour, the maximum brakecylinder pressure attainable is that determined by the safety valve 201.

Also, similarly to the valve mechanism l8 shown in Figure 1, the valvedevices 2 and 268 function during a full service application of thebrakes to reduce brake cylinder pressure at the time the speed of thetrain is reduced to a relatively low speed such as ten or fifteen milesper hour, degree to which the brake cylinder pressure is reduced toprevent sliding of the wheels being different however, depending uponthe speed of the train being above or below the predetermined speed ofsixty miles per hour at the time that the service application of thebrakes is initiated.

In the event of breakage of the driving belt 55! of the governor devicel9 or disengagement of the belt i5! from the associated pulleys, and theconsequent opening of the switch device 23 as previously described, theelectromagnet of the magnet valve device 2l2, in the embodiments shownin Figures 3 and 4, remains deenergized. Thus, upon the initiation of anemergency application of the brakes at a time that the train istraveling in excess of the predetermined high speed of sixty miles perhour, the controlling valve devices 2 l I and 268 function to cut offthe supply of fluid under pressure to the brake cylinder l6 when apressure of seventy-five pounds per square inch and corresponding to abraking ratio of one hundred and fifty per cent is attained. In suchcase, therefore, the .usual braking ratio of one hundred and fifty percent effected by standard passenger car equipment is attained.Furthermore, since no variation in the fluid pressure on thedifferential diaphragm valve devices 2 and 268 is effected at the timethe speed of the train reduces to the relatively low speed of ten orfifteen miles per hour, the full braking ratio of one hundred and fiftyper cent is maintained until the train is brought to a complete stop.Thus in the event of the opening of the switch device 23, theembodiments shown in Figures 3 and 4-. function to produce the samebraking effect as does present standard passenger car brake equipment.

In the event of a service application of the brakes being initiated at atime when the switch device 23 is open, the valve devices 2 and 268 ofthe embodiments, shown in Figures 3 and respectively, are likewiseinoperative to effect any reduction in brake cylinder pressure at thetime the speed of the train is reduced to the relatively low degree often or fiteen miles per hour, because the magnet valve device 248 is notenergized and therefore no variation in the fluid pres-- sure acting onthe diaphragms of the valve devices 2H and 268 is effected.

The embodiment of our invention shown in Figure 5, differs from theembodiment shown in Figure 1 in the provision of a different type ofvalve mechanism 281 in place of the valve mechanism I8.

The valve mechanism 28] comprises, essentially, a pair of magnet valvedevices 282 and 283, respectively, embodied in a casing 284 and having apair of blow-down valves 285 and 28% associated with the magnet valvedevices 282 and 283, respectively. The magnet valve device 282 comprisesan electromagnet 288, and a valve 289 actuated by the electromagnet 288.289 is disposed in a chamber 29l which is in constant communication withthe blow-down valve 285 through a passage 292 and has a fluted stem 293which extends through a bore 294 into a chamber 295. A coil spring 296,disposed in the chamber 295 and interposed between a collar or flange onthe fluted stem 293 and a screw plug 29'! closing the chamber 295,normally yieldingly urges the valve 289 away from its associated valveseat 298 to open communication between the chamber 295 and the chamber23!. Upon energization of the electromagnet 288 the valve 2&9 isactuated into seated position on the valve seat to close communicationbetween the chamber 235 and the chamber 2!", against the force of thespring 295.

The magnet valve device 33 comprises an electromagnet and a valveactuated by the electromagnet si l. The valve is disposed in a chamberSilt which is in constant communication with the chamber 235 of themagnet valve device through a passage 304, and is normally yieldinglyurged into seated relation on its associated valve seat 365 by a coilspring 38%, disposed in the chamber 3&3 and interposed be- The valvetween the valve and a screw plug 3i]? which closes the chamber 353. Uponenergization of the electromagnet 36!, the valve 302 is unseated fromits valve seat against the force of the spring tilt, and communicationis thereby established from chamber 303 to a chamber 309 through a boreall through which the fluted stem 300 of the valve extends. The chamber309 is in constant communication with the blow-down valve 286 through apassage M2.

The brake cylinder [16 is supplied with fluid under pressure from thebrake cylinder port of brake controlling valve device l5 through a pipedid, the switch device 2! also being supplied with fluid under pressurethrough a branch pipe 355 opening out of the pipe did, the pipe 3M beingconnected also to the passage 304 of the valve mechanism 28! through abranch pipe 3E6.

The electromagnets 288 and 30! of the valve mechanism 28! arecontrolled, respectively, in the same manner as are the electromagnets9B and H22 of the valve mechanism l8 shown in Figure 1, the circuit forenergizing the electromagnet 288 being completed through the governordevice and the contact members of the switch device 2i upon anapplication of the brakes initiated at the time the train is travelingat a speed in excess of the predetermined high speed of sixty miles perhour, and the circuit for the electromagnet 39! being completed throughthe governor device 49 and contact members of the switch device 2iwhenever the speed of a train reduces to a relatively low degree, suchas ten or fifteen miles per hour, following the initiation of anapplication of the brakes, whether the speed of the train at the time ofthe initiation of an emergency application of the brakes is in excess ofor less than the predetermined high speed of sixty miles per hour.

Assuming the auxiliary reservoir I2, the service reservoir it and theemergency reservoir I4 to be charged as described in the previouslydescribed embodiments, and assuming that the train is traveling at aspeed in excess of the predetermined high speed of sixty miles per hour,fluid under pressure is supplied to the brake cylinder 58, upon theinitiation of an emergency application of the brakes, under the controlof the brake controlling valve device i5, through the pipe 3M, theswitch device 2! being simultaneously actuated to circuit-closingposition by fluid under pressure supplied through the pipe 315.

Since the train is traveling at a speed in excess of the predeterminedhigh speed of sixty miles per hour, the electromagnet 288 of the magnetvalve device 282 is energized and the valve 289 is accordingly actuatedinto seated position on the valve seat 298. Accordingly, fluid underpressure is supplied to the brake cylinder [6 until the maximum degreeof pressure, such as one hundred pounds per square inch andcorresponding to a two hundred per cent braking ratio, is attained.

When the speed of the train is decreased to the relatively low speed,such as ten or fifteen miles per hour, the circuit for energizing theelectromagnet tilt of the magnet valve device 283 is completed throughthe governor device 58, and the valve 392 is accordingly unseated fromits valve seat 3535 to establish communication from the brake cylinder5% to the low-down valve through pipe 3M, branch pipe 3J5, pasnan sageecu, chamber 363, past the unseated valve emergency application of thebrakes.

392, through bore 3| I, chamber 389 and passage 312.

The setting of the blow-down valve 286 may be such that the brakecylinder pressure is reduced to any desired degree, such as fifty poundsper square inch, corresponding to a braking ratio of one hundred percent.

Thus as the speed of the train is decreased to a relatively low speedand just prior to stopping of the train, the braking ratio is decreasedfrom the relatively high braking ratio of two hundred per cent to abraking ratio of one hundred per cent, so that the train is brought to astop smoothly and with no sliding of the wheels or shock and discomfortto the passengers.

Release of the brakes following an emergency application of the brakes,as just described, being effected similarly as in previously describedembodiments, it is deemed unnecessary to specifically describe thisoperation.

If an emergency application of the brakes is initiated at a time whenthe train is traveling at a speed less than the predetermined high speedof sixty miles per hour, fluid under pressure is supplied to the brakecylinder l6 and to the switch device 2|, as in the previously describedHowever, the speed of the train being insufiicient, the circuit forenergizing the electromagnet 288 of the magnet valve device 282 is notcompleted through the governordevice i9 and therefore, valve 289 remainsunseated from its valve seat 298 and the ultimate fluid pressureattained in the brake cylinder i5 is accordingly determined by thesetting of the blow-down or safety valve 285, the brake cylinder itbeing in communication with the blow-down or safety valve 285 throughpipe 3M, branch pipe 316, passage 3M, chamber 285, bore past theunseated valve 289, through charm ber 29L and passage 292.

The setting of the safety valve 285 is such as to maintain a pressure inthe brake cylinder, such as seventy-five pounds per square inch, andcor-- responding to a one hundred and fifty per cent braking ratio. anemergency application of the brakes is initiated at a time when thetrain is traveling at a speed less than the predetermined high speed ofsixty miles per hour, the brake cylinder pressure is limited to adegree, such as seventy-five ii pounds per square inch, whichcorresponds to a braking ratio less than the bralnng ratio attained uponan emergency application of the brakes initiated at a time when thetrain is traveling at a speed in excess of the predetermined high speedof sixty miles per hour.

As the speed of the train decreases to a relatively low degree, such asten or fifteen miles per hour, the circuit for energizing theelectromagnet 305 of the magnet valve device 283 is completed throughthe governor device l9, and, as in the previously described emergencyapplication of the brakes for the embodiment shown in Figure 5,communication is thus established from the brake cylinder I 6 to theblow-down valve 28%;. Brake cylinder pressure is accordingly reduced tothe same degree of pressure determined by the adjustment of theblown-down valve 286, as in the case of an emergency application of thebrakes initiated at the time the train travels at a speed in excess ofthe predetermined high speed of sixty miles per hour. As in the previouscase, this reduction in the brake cylinder pressure prior to stopping ofthe train enables a smooth stop without sliding of the wheels.

It will thus be seen, that when Release of the brakes, following anemergency application of the brakes initiated at a time when the trainis traveling at a speed less than the predetermined high speed of sixtymiles per hour, being effected similarly as in previously describedoperations or embodiments, it is deemed unnecessary to specificallydescribe this operation.

The embodiment of our invention, shown in Figure 6, differs essentiallyfrom the embodiment shown in Figure 5, in the provision of a valvemechanism 32! in place of the valve mechanism 28!, whereby the brakecylinder pressure is controlled, according to the speed of the train,indirectly by magnet valve devices through the medium of relay valvedevices, controlled by the magnet valve devices, so as to obviate thecondition present in the embodiment shown in Figure wherein the magnetvalve devices directly control the brake cylinder pressure according tothe speed of the train.

The valve mechanism 32! comprises a magnet valve casing section 322 anda relay valve casing section 323, suitably secured together, by bolts orscrews, not shown, and having gaskets 324 and 325 interposedtherebetween.

Operating in a bore 328 in the casing section 323 is a valve piston 329,similar to the valve pistons 1! and)! of the embodiment shown in Figure1, the valve piston 329 having at one side a chamber 33! and at theopposite side a chamber 332. Inset in one face of the valve piston 329is an annular gasket 333 which is adapted to seat on an annular rib seat334 which is smaller in diameter than is the bore 328, the valve piston329 being urged into seated relation on the annular rib seat 334 by acoil spring 335 which is interposed in the chamber 33! between the valvepiston 329 and the casing section 322. Formed on the face of the valvepiston 329 opposite to that having the annular gasket 333 is an annularrib 336 which is adapted to seat in sealing relation against the gasket324 when the valve piston 329 is moved away from the annular rib seat334.

Formed in the face of the valve piston 329 open toward the chamber 332is a chamber or recess 338, a disc type valve 339 being guidably mountedin the chamber 338 and yieldingly urged outwardly of the chamber 338 bya coil spring 34! which is interposed in the chamber 338 between thevalve 339 and the valve piston 329. When the valve piston 329 is seatedon the rib seat 334 the valve 339 is yieldingly held in seated relationon an annular rib seat 342 and cuts off or closes communication from thechamber 332 to atmosphere through an atmospheric port or passage 343. Athreaded collar 344, screwed into the valve piston 329 at the open endof the chamber 338, serves to engage the guide lugs of the valve 339 andeffect unseating of the valve 339 from the annular rib seat 342 uponmovement of the valve piston 329 away from the annular rib seat 334.

The brake cylinder !6 is in communication with the chamber 332 at theone side of the valve piston 329, through pipe 3l4, a branch pipe 346, aloaded check valve device 341 and a passage 343. The check valve device341 comprises a ball check valve 43!, a loading spring 482 for urgingthe valve 48! to its associated seat, and an adjusting screw 483 forvarying the tension of spring 402.

A magnet valve device 35! is provided for controlling the supply offluid under pressure to and the release of fluid under pressure from thechamber 33! at one side of the valve piston 329. The magnet valve devicecomprises an electromagnet 353 and a pair of oppositely seating valves354 and 355, the valves being connected by a fluted stern 356 andsimultaneously actuated by the electromagnet 353. The valve 354 isdisposed in an atmospheric chamber 351, and the valve 355 is disposed ina chamber 358 which is in constant communication with a source of fluidsupply, such as the emergency reservoir !4, through a pipe 359. A coilspring 35!, disposed in the chamber 358 and interposed between the valve355 and a screw plug 362 closing the chamber 358, normally yieldinglyurges the valve 355 into seated relation on its associated valve seatand unseats the valve 354 from its associated valve seat.

Intermediate the chambers 35'! and 358 is a chamber 353, which is inconstant communication valve 354 in the normal position of the valves n354 and 335, and communication being out off between the chamber 363 andthe chamber 358 by the valve 355. When the electromagnet 353 isenergized, communication is opened from the chamber 363 to the chamber358 past the unseated valve 355, communication of chamber 363 with thechamber 351 being simultaneously cut off by valve 354.

A valve piston 361 is also provided which operates in a bore 368 in thecasing section 323 and which has a chamber 369 at one side thereof and achamber 3H at the opposite side thereof. Inset in one face of the valvepiston 361 is an annular gasket 312 which is adapted to seat on anannular rib seat 313 into which position the valve piston is yieldinglyurged by a coil spring 314, disposed in the chamber 369 and interposedbetween the valve piston 361 and the casing section 322. An annular rib315 is provided on the face of the valve piston open to the chamber 369,which rib is adapted to engage the gasket 325 in sealing relation, whenthe valve piston 361 is moved to the opposite extremity of its travelaway from the annular rib seat 313.

Guidably mounted in a recess or chamber 316 in the face of the valvepiston 361 open to the chamber 31! is a disc type valve 311 which isyieldingly urged outwardly of the chamber 316 by a coil spring 318interposed in the chamber 3'59 between the valve 311 and the valvepiston 361. When'the valve piston 361 is seated on the annular rib seat13 the valve 311 is yieldingly held seated on an annular rib seat 319 tocut off communication between the chamber 31! and an atmospheric exhaustpassage or port 38!. A threaded collar 383, screwed to the valve piston361 at the outer end of the chamber 316, is adapted to engage the guidelugs on the valve 311 and unseat valve 311 from the annular rib seat319, when the valve piston 361 is moved away from the annular rib seat313.

The brake cylinder #6 is in communication with the chamber 31! throughpipes 3H! and 346, a branch pipe 365, past a loaded check valve device386 and through a passe 7. The check valve device 338 is sim' tr to ileek valve device 341 and comprises hall check valve 4-93, loadingspring 433 for the valve 5-65, and an adjusting screw 481, the degree ofloading of the valve 405 being less than that of the check valve 43!, aswill be explained hereinafter.

A magnet device 383 is provided for controlling the supply of fluidunder pressure to and the reof fluid under pressure from the chamber 333at the one side of the valve piston 36!. The magnet valve device 338comprises an electromagnet and a double beat valve 33! which is actuatedby the electromagnet 339 and which is disposed in a chamber 332constantly connected to chamber 363 through a passage 393. The doublebeat valve has a fluted stem 334 which extends into a chamber 335, and acoil spring contained in the chamber 395 in interposed relation betweena collar or flange on the end of the fluted stem 394 and a screw plug33? which closes the chamber 395, yieldingly urges the double beat valve33! into a position such that communication is established from thechamber 332 to the chamber 395. The chamber 395 is in constantcommunication with the chamber 358 of the magnet valve device 35!,through a passage 398.

Upon energization of the electromagnet 339,

the double beat valve 39! is shifted to a position such that thecommunication between the chamber 3352 and the chamber 395 is cut offand a communication is established from the chamber 332 to anatmospheric chamber 339.

The electromagnets 353 and 339 are controlled, respectively, in the samemanner as are the electromagnets 288 and 33! of the embodiment shown inFigure 5, by the governor device 19 and the switch device 2!.

Assuming the brake pipe the auxiliary reservoir iii, the servicereservoir 3 and the emergency reservoir !4 to have been charged, aspreviously described, the equipment being conditioned as shown in Figure6, and that an emergency application of the brakes is initiated at thetime the train is traveling at a speed in excess of the predeterminedhigh speed of sixty miles per hour, fluid under pressure is suppliedthrough pipe 3M to the brake cylinder I6 and the switch device 2!.

The electrcmagnet 353 of the magnet valve device 355 having beenenergized by actuation of the switch device 2! to circuit-closingposition, as before described, the magnet valve device 35! is actuatedto the position for supplying fluid under pressure from the emergencyreservoir 23 to the chamber 33! through pipe 359, chamber 358, pastunseated valve 355, through chamber 333, and passage 333. Thus both thefluid under pressure in chamber 33l and the tension of the spring 335act to maintain the valve piston 323 seated on the annular rib seat 334.

When the brake cylinder pressure has been built up sufficiently tounseat the ball valve 335 of the check valve device 3-3? against thetension of the loading spring 432, fluid under pressure is supplied fromthe brake cylinder supply pipe 3M, through the pipe 333, past the valve435, and through passage 343 to the chamber 332, where it tends tounseat the valve piston 32%] from the annular rib seat 334. However,since a relatively high emergency reservoir pressure is acting on theopposite face of the valve piston, the valve piston 323 is maintained inseated relation on the annular rib seat 334, against the brake cylinderpressure. Thus, due to the tension of the spring 354 and the pressure ofthe fluid which flows past the valve into the chamber 338, the valve 333is held tightly against the annular rib seat 332 and exhaust of fluidunder pressure from the chamber 332 and accordingly from the brakecylinder !3 is prevented.

As will be explained hereinafter, the check valve device 34'! isadjusted so as to require a pressure in excess of a predetermineddegree, such as seventy-five pounds per square inch and corresponding toa braking ratio of one hundred and fifty per cent, in order to permitflow of fluid under pressure therepast.

In view of the fact that the maximum pressure attainable in the brakecylinder I6 is as previously explained, a degree substantially higherthan that determined by the check valve device 341, namely, a maximumpressure of, for example, one hundred pounds per square inch, andcorresponding to a braking ratio of two hundred per cent, and sincedespite the unseating of the check valve device 34'! fluid underpressure is prevented from escaping past the valve 333 and through theexhaust port of the brake cylinder !3, the brake cylinder pressure isbuilt up to the maximum degree, that is for example, to one hundredpounds per square inch and corresponding to the maximum braking ratio oftwo hundred per cent.

The electromagnet of the magnet valve device 338 being deenergized atthis time, the supply of fluid under pressure from the emergencyreservoir M to the chamber 339 at the one side of the valve piston 33!is maintained through pipe 359, chamber passage 393, chamber 395, pastvalve 39!, through chamber 392 and passage 393. Thus brake cylinderpressure acting in chamber 3' on the face of the valve piston 35?,through the pipe 385, past the loaded check valve 435 and throughpassage 38'!, is ineffective to unseat the valve piston 36? from theannular rib seat 313 and reduction in brake cylinder pressure by ventingof fluid under pressure past the loaded check valve device 333 isprevented because the valve 3' is maintained seated on the annular ribseat 319.

Thus the two hundred per cent braking ratio is effective to deceleratethe train from the high speed in excess of the predetermined high speedof sixty miles per hour until the speed of the train is decreased to arelatively low degree, such as ten or fifteen miles per hour, at whichtime the governor device !9 completes the circuit for energizing theelectromagnet 383 of the magnet valve device 333. The double beat valve39! is accordingly actuated to cut off the communication through whichfluid is supplied from the emergency reservoir M to the chamber 333 andto open communication from the chamber 339 to the atmospheric chamber339 to vent fluid under pressure from the chamber 369.

The brake cylinder pressure acting in chamber 3'5! on the face of thevalve piston 35'! thus becomes effective to overcome the tension of thespring 374 and, upon unseating of the valve piston 33'! from the annularrib seat ("M3, the entire face of the valve piston is subjected to brakecylinder pressure which then causes the valve piston 36'! to be suddenlyshifted or snapped to the opposite extremity or position in the bore333, in which position the annular rib 3E5 seals against the gasket 325to prevent leakage of fluid under pressure past the valve piston 33'!from the chamber 3']! to the chamber 339 and to atmosphere.

The ball check valve 405 of check valve device 383 is loaded by thespring 333 to any desired degree, such as fifty pounds per square inch,corresponding for example to a one hundred per cent braking ratio. Thuswhen the Valve 311 in the valve piston 361 is unseated from the annularrib seat 319 by movement of the valve piston 361 to its upper positionas just described, fluid under pressure is vented from the brakecylinder through pipes M4 and 346, branch pipe 385, past the check valvedevice 386, through passage 381, chamber 31!, past the unseated valve311, and through the exhaust port or passage 38!. When the pressure offluid in the brake cylinder has been reduced to a degree slightly belowthe adjustment of the check valve device 386, the ball check valve 405of the check valve device 386 is urged by the loading spring 406 intoseated relation on its valve seat to cut off the further release offluid under pressure from the brake cylinder.

Thus, at the time the train speed is reduced to a relatively low degree,the braking ratio is reduced from a relatively high degree of twohundred per cent to a relatively low degree of one hundred per cent, andas in previous instances, the train is brought to a smooth stop with noshock or discomfort to the passengers and without sliding of the wheels.

Release of the brakes following an emergency application of the brakeseffected in the manner just described, is effected in a manner similarto that described in previous embodiments, and it is deemed unnecessary,therefore, to specifically describe this operation.

If an emergency application of the brakes is initiated at a time thatthe train is traveling at a speed less than the predetermined high speedof sixty miles per hour, the circuit for energizing the electromagnet353 of the magnet valve device 35! is not completed through the governordevice 19, and consequently, the chamber 33! at the one side of thevalve piston 329 is connected to atmosphere through the passage 364,chamber 363, past the unseated valve 354, and through the atmosphericchamber 351. Thus fluid under pressure is supplied to the brake cylinder!6, as in the previously described emergency application of the brakes,until pressure of the fluid unseats the ball check valve 40! of theloaded check valve device 341, which as previously explained, isadjusted to maintain a pressure such as seventy-five pounds per squareinch, corresponding to a braking ratio of one hundred and fifty percent. The supply of fluid under pressure past the check valve device 341to chamber 332 through the passage 348 then becomes effective tosuddenly and positively shift the valve piston 329 away from the annularrib seat 334 against the tension of the spring 335 into the positionwherein the annular rib 336 seals against the gasket 324. In moving tothis position, the threaded collar 344 on the valve piston 329 engagesthe guide lugs on the disc valve 339 and unseats the valve 339 from theannular rib seat 342 so that the passage 348 is connected to atmos pherethrough the chamber 332, past the unseated valve 339, and through theatmospheric exhaust passage 343.

It will, therefore, be seen that the pressure of the fluid supplied tothe brake cylinder !6 cannot exceed the degree of pressure as determinedby the loaded check valve device 341, because excess pressure isimmediately relieved through the atmospheric exhaust passage 343.

Thus, when an emergency application of the brakes is initiated at a timewhen the train is traveling at a speed less than the predetermined highspeed of sixty miles per hour, a braking ratio of one hundred and fiftyper cent is attained as compared to a braking ratio of two hundred percent attained when an emergency application of the brakes is initiatedat a time that the train is traveling at a speed in excess of thepredetermined high speed.

As in the previously described emergency application of the brakes, thevalve piston 361 is held seated on the annular rib seat 313 by thepressure of the fluid supplied to the chamber 369 from the emergencyreservoir !4 through pipe 359, chamber 358, passage 398, chamber 395,past valve 39!, through chamber 292, and passage 393. Accordingly, thevalve 311 is held seated on the annular rib seat 319 to prevent exhaustof fluid under pressure from the brake cylinder past the check valvedevice 386.

The speed of the train is reduced, under a braking ratio of one hundredand fifty per cent, until the relatively low speed, such as ten orfifteen miles per hour is reached, at which time the circuit forenergizing the electromagnet 389 of the magnet valve device 388 iscompleted through the governor device l9. The double beat valve 39! ofthe magnet valve device 388 is accordingly shifted to cut off the supplyof fluid under pressure to the chamber 369 at the one side of the valvepiston 361 and to establish communication through which the fluid underpressure in the chamber 369 is vented to atmosphere.

The loaded check valve device 386 being adjusted to maintain a pressure,such as fifty pounds per square inch, and corresponding to a brakngratio of one hundred per cent as previously explained, fluid underpressure is released from the brake cylinder !6 through pipes 3!4 and346, branch pipe 385, past the check valve device 386 through passage381, chamber 31!, past the unseated valve 311, and through the exhaustpassage 38!, until reduced sufficiently to cause reseating of the checkvalve 405 of check valve device 386.

Thus, a short interval before the train is brought to a stop, thebraking ratio of one hun dred and fifty per cent is reduced to a brakingratio of one hundred per cent, and as in previous cases, the train isaccordingly brought to a smooth stop without shock or discomfort to thepassengers and without sliding of the wheels.

Release of the brakes, following an emergency application of the brakesinitiated at a time that train is traveling at a speed less than thepredetermined high speed of sixty miles per hour, is effected as inpreviously described embodiments,

and it is therefore deemed unnecessary to specifically describe thisoperation.

It will be noted that the embodiments shown in Figures 5 and 6 functionduring a service application of the brakes in the manner above describedin connection with the embodiment shown in Figure 1. Since the blow-downvalve 285 of the valve mechanism 28! and the loaded check valve device341 of the valve mechanism 32! are adjusted to relieve pressure only ata degree such as seventy-five pounds per square inch, which is in excessof the usual sixty-three pound setting of the safety valve 201associated with the brake controlling valve device !5, the maximum brakecylinder pressure attainable during a service application of the brakesis that determined by the setting of the safety valve 201. Thus, boththe Valve mechanism 28! and the valve mechanism 32! are ineffective toproduce a braking ratio higher than the usual braking ratio effected bypresent standard braking equipment on passen-

